VARIETAL RESPONSE TO SULPHUR LEVELS AND SOIL SULPHUR FRACTIONS UNDER DIFFERENT RICE ESTABLISHMENT METHODS

Abstract

A field experiment was conducted during Kharif and Rabi seasons of 2025 at Indian Institute of Rice Research, Hyderabad, to evaluate the effect of graded levels of elemental sulphur on soil sulphur fractions in different rice establishment methods and varieties. The experiment was laid out with two crop establishment methods [direct seeded rice (DSR) and transplanted rice (TPR)], two rice varieties (Kamala and Samba Mahsuri) and four sulphur levels (0, 20, 40 and 60 kg S ha-1) in a split-split plot design with three replications. The soil samples were collected from 0–15 cm depth of the experimental plots at the end of each season and analysed for water-soluble sulphur, sulphate sulphur, inorganic sulphur, organic sulphur, residual sulphur and total sulphur. The results showed that sulphur application significantly influenced all sulphur fractions. DSR recorded higher water-soluble, sulphate and inorganic sulphur contents, whereas TPR showed higher organic and residual sulphur. The application of 40 kg S ha-1 produced the maximum content of water-soluble sulphur (9.12 and 10.16 mg kg-1), sulphate sulphur (16.47 and 17.00 mg kg-1), inorganic sulphur (23.07 and 24.94 mg kg-1), organic sulphur (229.82 and 224.05 mg kg-1) and total sulphur (308.57 and 305.84 mg kg-1) during Kharif and Rabi, respectively. Residual sulphur decreased up to 40 kg S ha-1 which indicated its transformation into more available sulphur in both the seasons. Kamala recorded higher available sulphur fractions than that of Samba Mahsuri. The study concluded that elemental sulphur at 40 kg ha-1 was the optimum level for improving sulphur availability and its accumulation in soil under different rice establishment methods.